My 620 Build

[Lachlan]

Great thread! Looks like we were tackling similar issues around the same time.

 

Keen to see how this progresses.

[RyanC]

I haven't aired up the tyres in a while and looks like one rear has a slight wall crack.  Hopefully good enough to put her on the weigh bridge 10 mins away.  265 is a lot of rubber behind the massive 100hp💪 might see how good the diff is on the way back.  😏😏

[RyanC]

Diff drained and filled with gl5.

 

Since when did 4 speeds have 10mm Allen filler plugs! Gonna have to find/buy another tool.  Getting closer.

[thisismatt]

On 8/18/2023 at 8:41 AM, RyanC said:

Diff drained and filled with gl5.

 

Since when did 4 speeds have 10mm Allen filler plugs! Gonna have to find/buy another tool.  Getting closer.

In a pinch you could try a 10mm bolt, either with a couple nuts jammed on it, or a bar welded to it 😛

[RyanC]

I found my 8 and 10mm Allen keys...it's neither so guessing 7/16 or 9...def  ring in

[datzenmike]

Differential and transmission bungs are usually square hole that a 3/4" ratchet will fit.

 

[RyanC]

21 hours ago, datzenmike said:

Differential and transmission bungs are usually square hole that a 3/4" ratchet will fit.

 

Yep diff was sorted with the long ratchet, someone did the filler up bloody tight! but it has sat for who knows how long.

 

Gearbox has a square "NUT" for the drain and an allen for the filler grrrr.  Def not 8 or 10mm.  Cant see it being 9mm so 3/8 should do the job.

[Lachlan]

In case I missed it and you got rego, there’s an event up your way once a month that I’m hoping to get along to. Next one is this Sunday from 8am at Village Coffee Hub, Cameron Park. Details below if you’re interested.

 

Cars & Coffee by NSCC

https://facebook.com/events/s/cars-and-coffee-by-nscc-at-vil/937386487550865/

 

There’s a usually one on the Central Coast every weekend (different hosts) and I’m trying to get along to at least one a month with my 1200. Make sure you come over and say Hi if you see me.

[RyanC]

17 hours ago, Lachlan said:

In case I missed it and you got rego, there’s an event up your way once a month that I’m hoping to get along to. Next one is this Sunday from 8am at Village Coffee Hub, Cameron Park. Details below if you’re interested.

 

Cars & Coffee by NSCC

https://facebook.com/events/s/cars-and-coffee-by-nscc-at-vil/937386487550865/

 

There’s a usually one on the Central Coast every weekend (different hosts) and I’m trying to get along to at least one a month with my 1200. Make sure you come over and say Hi if you see me.

Thanks I'll let you know when I'm heading in to one.  Rego hopefully in next 3 weeks.

[RyanC]

9mm found and sorted, Just needs a fill.

[RyanC]

Well took the girl for a spin...well after I got her stuck on the wet grass that is woops.  Quick tow out 3 laps of town.

 

Pretty sure she was pinging so timing and points check next up ....brakes....work but pretty daggy ..with drums is it worth getting them hot ...hitting them hard 2 or 3 times at say 40.and 30.mph....70 to 60 kmh?  Pulling to the left slightly so looks like small adjustment needed.

 

Felt like no booster so swapped vacuum line and now booster is working...the old line appeared to have a 1 way valve is this needed?

 

 

[datzenmike]

Also the intake vacuum varies, certainly it drops quite low under load. If floored and intake vacuum is only a few inches of mercury and you have to hit the brakes suddenly there won't be time for the booster to build vacuum. YES the one way valve is needed. It keeps vacuum in the booster so that the brakes will work even if the engine were to stall. You would get at least one good pump on the brakes probably two before it's exhausted.

 

 

 

[datzenmike]

On 8/20/2023 at 4:05 PM, RyanC said:

Yep diff was sorted with the long ratchet, someone did the filler up bloody tight! but it has sat for who knows how long.

 

Gearbox has a square "NUT" for the drain and an allen for the filler grrrr.  Def not 8 or 10mm.  Cant see it being 9mm so 3/8 should do the job.

 

The square is less common and nothing but an adjustable wrench really fits it. The transmission and differential bungs are the same. The drain bungs have a magnet on them so I use drain bungs in place of the fill bungs.

[Stoffregen Motorsports]

I don't like having the magnetic plug in the higher location. Bits may stick to it for a moment and then fall. I'd rather have those bits sitting in the bottom.

[RyanC]

8 hours ago, datzenmike said:

Also the intake vacuum varies, certainly it drops quite low under load. If floored and intake vacuum is only a few inches of mercury and you have to hit the brakes suddenly there won't be time for the booster to build vacuum. YES the one way valve is needed. It keeps vacuum in the booster so that the brakes will work even if the engine were to stall. You would get at least one good pump on the brakes probably two before it's exhausted.

 

 

 

Thanks Mike so I should have vacuum to the booster eg flows air from booster to intake but not intake to booster.

[RyanC]

Thankfully the magnetic square but was the drain plug.  Pretty messy cleaned up the drain plug lots of fine shit..but new gl4 in untill it dripped out the filler.

[RyanC]

Reading through it seems I noted the main jets as 110 and 130 which is a weird combo, and from reading very lean for an L20, needs to be 140 or 145 ish which would be why she pings so badly.  Next up to remove and check again and if they are that small I might swap them and see if better under partial throttle but will order a set of larger jets to try.

[datzenmike]

L20B Hitachi???? primary are anywhere between 99 and 112 so just over 100 on average. My 710 came with 99s but from a high altitude state. It ran so much better with 112s at sea level. Secondaries are usually 150 to 160. There is no set answer to the jet sizes, it's based mostly on altitude. Higher runs smaller jets, lower altitude needs more gas so larger jets.

 

Don't forget the power valve. There are two screws (of the four) that go up through the throttle plate base of the carburetor into the main body. One is hollow to allow a vacuum signal up to the power valve mechanism. These are easily put in the wrong holes making it inoperative. The hollow screw goes in the front of the carburetor below the float chamber. Under full throttle the power valve forces a rich condition for maximum power for passing or acceleration. Yes mine had been apart before and was put back together wrong. The difference is noticeable when the secondary tips in.

 

 

On 9/1/2023 at 2:20 PM, RyanC said:

Thanks Mike so I should have vacuum to the booster eg flows air from booster to intake but not intake to booster.

 

Yes the one way allow air out of the booster but not back in.

[RyanC]

Thanks Mike...it's a Weber 😂 good ole 32/36.  Searching the web and Ratsun around 140 and 145 seems the go.

 

Has. Hesitation in throttle up ...axel pump works as I replaced diaphragm..

 

Reading a guide online if the mains are too lean it will create hesitation as well.  Gonna pull them and confirm today.

[RyanC]

Been a short minute.  Broke my arm 6 wks ago.  Have some permanent structural steelwork installed an almost back to normal.  Man on dirtbike vs tree on a trail.  Anyway.l, finally my jet kit arrived I've bumped up to a 50 idle main 45 secondary..seems on the rich side but with the two 45s I def had hesitation off idle.  Gone to 145 in each for mains.  Def seems better in neutral will go for a nite drive this week and see how it drives 

 

Timing is at 11 def.  

 

One question .. actually two.

 

What size if anyone knows are the top door internal.handle not the big arm rest and the door opener backer bolts they are different and PO didn't have them it seems .

[Dusten]

The hesitation off idle isn't from your idle jets.  It's from the accel pump jet.  

[RyanC]

1 hour ago, Dusten said:

The hesitation off idle isn't from your idle jets.  It's from the accel pump jet.  

That's what I would have thought but my reading said otherwise.  And if you gently accelerate the pump isn't in action I don't think.  

 

My reading and investigations seems it's a mix of idle and mains.  Possibly emulsion tubes as well.  It's def happier and no real pumping or issues so will see how it drives

[RyanC]

Looking okay in the sun time for a wash

[Stoffregen Motorsports]

It would look cool with some belly boxes.

[RyanC]

5 hours ago, Stoffregen Motorsports said:

It would look cool with some belly boxes.

Yep it would the tray sits high and is not flat.  Plan will be to bag it and thinking a pull out draw system behind the cab for compressor etc then maybe some.aide.boxes we will see.

 

Was still pinging that day uppedy jets and swapped the emulsion tubes as the primary didn't have holes at bottom but had them up top so hopefully better on the secondary on its next trip out